Ferranti Audio Frequency Transformers - UK Vintage Radio Repair and Restoration Discussion Forum

BigPhil · 29th Oct 2018, 1:47 am

Hello!

I have acquired two Ferranti audio frequency transformers. One is in a box, it says it's an A.F.6. tTe other looks like it has previously been taken apart and reassembled, although I can't be sure as I literally know nothing about these items.

I was just wondering if anyone can give me any info on what they were used for and what they may be worth. They are interesting looking pieces, but that's just about all I can tell about them!

Thank you for your time.

rontech · 29th Oct 2018, 10:02 am

If you key " Ferranti Audio Frequency Transformers A.F. 6 " into google, a range of links comes up. There appears to be a number of items in the AF 1 and upwards series.

David Simpson · 29th Oct 2018, 11:39 am

Phil,
They were used in battery powered TRF Rx's from the 1920's & early 30's. Regards, David

HamishBoxer · 29th Oct 2018, 4:01 pm

Main point,put an Ohms meter across to make sure they are not open circuit.

BigPhil · 29th Oct 2018, 4:27 pm

Thanks for the info, everyone!

Does anybody have any idea of the likely value of these, please?

Argus25 · 30th Oct 2018, 12:40 am

Due to the fact they have a limited frequency response and are little use for any HiFi "Audiophile" application the prices are still sensible and probably below 20 or 30GBP depending on condition. I have experimented with a number of these transformers and they are ideal for AM radio use and under the right circumstances, the interstage and output transformers are capable of a fairly flat response from around 100Hz to 8 or 10KHz. Typically they were used in 1920's era TRF radios and in that era, many of the speaker systems could barely do a few hundred Hz to 5kHz.

Ed_Dinning · 14th Nov 2018, 10:49 pm

Hi Phil, nice to meet you art Golborne and I trust you had a good day.

Further thoughts on your transformers, there was a thread on the forum about modulating CRT's with a transformer isolated signal.
Your transformers may well work for this purpose and should have a good bandwidth for this application.

Ed

29th Oct 2018, 1:47 am	#1
BigPhil Retired Dormant Member Join Date: Oct 2018 Location: Manchester, UK. Posts: 2	Ferranti Audio Frequency Transformers Hello! I have acquired two Ferranti audio frequency transformers. One is in a box, it says it's an A.F.6. tTe other looks like it has previously been taken apart and reassembled, although I can't be sure as I literally know nothing about these items. I was just wondering if anyone can give me any info on what they were used for and what they may be worth. They are interesting looking pieces, but that's just about all I can tell about them! Thank you for your time.

29th Oct 2018, 10:02 am	#2
rontech Heptode Join Date: Jun 2017 Location: Southport, Merseyside, UK. Posts: 646	Re: Ferranti Audio Frequency Transformers If you key " Ferranti Audio Frequency Transformers A.F. 6 " into google, a range of links comes up. There appears to be a number of items in the AF 1 and upwards series. __________________ Time flies like an arrow, fruit flies like a banana

29th Oct 2018, 11:39 am	#3
David Simpson Nonode Join Date: Mar 2008 Location: Aberdeen, UK. Posts: 2,852	Re: Ferranti Audio Frequency Transformers Phil, They were used in battery powered TRF Rx's from the 1920's & early 30's. Regards, David

29th Oct 2018, 4:01 pm	#4
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,931	Re: Ferranti Audio Frequency Transformers Main point,put an Ohms meter across to make sure they are not open circuit. __________________ G8JET BVWS Archivist and Member V.M.A.R.S

29th Oct 2018, 4:27 pm	#5
BigPhil Retired Dormant Member Join Date: Oct 2018 Location: Manchester, UK. Posts: 2	Re: Ferranti Audio Frequency Transformers Thanks for the info, everyone! Does anybody have any idea of the likely value of these, please?

30th Oct 2018, 12:40 am	#6
Argus25 No Longer a Member Join Date: Oct 2016 Location: Maroochydore, Queensland, Australia. Posts: 2,679	Re: Ferranti Audio Frequency Transformers Due to the fact they have a limited frequency response and are little use for any HiFi "Audiophile" application the prices are still sensible and probably below 20 or 30GBP depending on condition. I have experimented with a number of these transformers and they are ideal for AM radio use and under the right circumstances, the interstage and output transformers are capable of a fairly flat response from around 100Hz to 8 or 10KHz. Typically they were used in 1920's era TRF radios and in that era, many of the speaker systems could barely do a few hundred Hz to 5kHz.

14th Nov 2018, 10:49 pm	#7
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: Ferranti Audio Frequency Transformers Hi Phil, nice to meet you art Golborne and I trust you had a good day. Further thoughts on your transformers, there was a thread on the forum about modulating CRT's with a transformer isolated signal. Your transformers may well work for this purpose and should have a good bandwidth for this application. Ed